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Analysis of CMMB mobile TV chip SC6600V and its application scheme
China Mobile Digital Multimedia Broadcasting (CMMB) is a mobile multimedia broadcasting standard with independent intellectual property rights issued by the State Administration of Radio, Film and Television as an industry standard. Spreadtrum Communications Co., Ltd. launched the industry's first CMMB standard single-chip solution SC6600V for mobile TV in May 2008. SC6600V not only has a flexible system solution, but also based on Spreadtrum's mobile phone baseband chip and mobile multimedia chip, it can develop product solutions that support China's independent intellectual property standards.
High-performance, low-power mobile TV chip
At present, most of the chip products that support the CMMB standard are channel demodulation chips, which must be equipped with an external source decoding processor chip to complete the source decoding, so as to truly realize the function of mobile TV. SC6600V is the industry's first high-performance, low-power chip that integrates CMMB demodulation and H.264 source decoding. Its increased integration directly brings benefits such as reduced power consumption and cost, rich peripheral interfaces and flexible The function selection adds value-added space to this chip and expands its application field.
The functional division of SC6600V mainly includes a high-performance microprocessor, a CMMB demodulator, a video and audio decoder, a power management unit, and a wealth of general peripheral interfaces (including external storage controllers and display controllers, etc.) ), Each functional module uses a modular design, the modular design makes the entire chip has a very good reliability and flexibility. The main features of this chip are as follows:
Rich peripheral interface: The input signal of SC6600V supports the intermediate frequency signal received from Tuner, or it can be the MFS stream after demodulated by the CMMB channel. Therefore, in addition to supporting intermediate frequency input signals, SC6600V can also support external mainstream CMMB demodulator, providing a flexible input interface. In terms of video output, it supports the decoded video YUV standard output, and can be directly output to the LCD display for display. It also supports bypassing the video decoder and outputting the MFS stream directly. These two options can be determined according to the different application schemes. Audio output supports I2S interface. In addition, there are many rich peripheral interfaces that can facilitate the expansion of product application solutions.
Flexible channel demodulation: The channel demodulation module fully supports the CMMB standard signal transmission and multiplexing specifications, and demodulates the intermediate frequency signal into an MFS stream and outputs it to other modules. In the standard frequency range, the functional modules of the physical layer of the broadcast channel of the mobile multimedia broadcasting system are implemented, and the frame structure, channel coding, modulation technology, and transmission instruction information of the transmission signal of the physical layer of the mobile multimedia broadcast channel are completed. It can support multiple channel coding and modulation methods to meet different signal quality requirements of different services and different transmission environments.
Multi-standard source decoding: The source decoding module supports H.264 video decoding standard and various popular audio decoding standards (such as MPEG1 audio layer 1/2, MP3, AAC LC and AAC + (LP), etc.), with the highest sampling rate It can reach 48kHz, the decoding rate can be up to 320Kbps, and supports dual channels. And it is completely possible to support the newly added standards by updating the firmware.
Full-featured video post-processing: the display image can support WQVGA, QVGA, CIF, QCIF, etc., and can realize the zoom function of the decoded video to adapt to different display screens, thus supporting the chip to terminal product display screen size from the hardware Self-adaptation, expanding the range of product applications. Support three logical layers (background layer, image layer and video layer). Corresponding technical measures are adopted for image jitter and color correction.
Stable power management: The chip itself integrates a power management unit to support power management functions such as standby and power-on. In addition, this unit can not only support on-chip power supply, but also provide power to off-chip chips, which can be used in certain applications. In this case, the system power consumption can be greatly reduced. The core voltage of the chip is 1.8V, and the I / O interface voltage is 1.8 ~ 3.3V. The high-performance main control CPU module is mainly responsible for the operation of the application software and the internal interrupt processing function of the chip, and provides a complete debugging interface in the debugging of the chip, such as the JTAG interface.
Software platform is stable and perfect
In order to shorten the customer's design time and enhance its product development capabilities, SC6600V provides a comprehensive set of universal interfaces for drivers and application software, which can provide rapid and effective customer software design. At the same time, the general interface and optimization space of product differentiation design are considered. It provides a flexible platform foundation for the expansion of upper-layer business functions and software optimization.
The underlying software is flexible and stable: the scalability of the product is considered in the development of the firmware program, such as audio decoding can be updated to update the firmware to support the new standard, and the transmission layer can be replaced by updating the firmware or adding conditional access (CA) Modules etc. The module driver is well developed, from peripheral interfaces to channel demodulation, from video decoding to audio decoding, from graphics processing to various signal output modules, all have stable and perfect drivers, which will be provided to users as chip software libraries. However, because the development of the underlying software and the customer's differentiated design are transparent, the underlying software is not user-developable.
Powerful application software expansion performance: The application software based on real-time operating system adopts the design idea of ​​standardization and modularization, so that new business applications can be expanded on different system platforms according to Spreadtrum's standard interface. The middleware including ESG and Play / Record Engine can be updated and re-expanded. For different application product terminals such as mobile TV, PMP and USB TV stick, the software platform of SC6600V has been perfected and scientifically designed. Make customers' products go to market quickly.
Large space for product differentiation design: Although similar products have not yet flooded the market, Spreadtrum has already considered the issue of product differentiation in the software design of SC6600V. It can provide different application platforms for different users, flexible GUI design, and support different CAs. SC6600V products will provide customers with a complete set of SDKs, from low-level drivers / firmware to adaptation layer software / API, to middleware and application software for different end products.
Flexible application solution
SC6600V can support two system platform integration methods: one is a handheld TV terminal system that cooperates with external main control equipment, such as a mobile TV platform that cooperates with Spreadtrum's GSM / GPRS chip series and TD-SCDMA baseband chip series. These external master chip designs can communicate with SC6600V. The external processor only controls and processes the SC6600V in a small amount. Such a design will ensure its flexible integration with various RF front-end and back-end application processors.
The other is an independent handheld TV terminal system that does not require external main control equipment. SC6600V supports an independent single-chip system platform (no external processor is required). As a single-chip system platform, it is mainly used in portable mobile multimedia terminals, such as PMP and TV sticks, etc. At this time, SC6600V mainly starts the system from an external E2PROM or T-Flash card. From the scope of SC6600V application system, it is mainly used in mobile devices, personal media players and other portable electronic design products.
Mobile TV solutions
SC6600V can be combined with several baseband chip series from Spreadtrum to form a chipset to design a 2G / 3G mobile TV terminal. In this way, CMMB + GSM and CMMB + TD-SCDMA schemes can be realized.
PMP and USB TV stick solutions
For portable terminal products such as PMP and USB TV sticks, SC6600V has demonstrated the advantages of single-chip solutions. Only a few external devices such as high-frequency heads and memories can be used to implement the whole machine solution.
PMP and USB TV stick solutions
Summary of this article
At present, the mobile phone TV function can basically only be realized on expensive smart phones, and the SC6600V single-chip solution allows mobile phone manufacturers and operators to push mobile phone TV services to the mainstream feature phone market and control costs in a reasonable range Inside. With the successful development of the SC6600V chip, Spreadtrum will provide the industry with a full range of mobile TV terminal solutions to promote mobile TV to enter the mass market, thereby meeting the commercial needs of mobile TV services.
Chengdu Xinruixin Optical Communication Technology Co.,Ltd , https://www.xrxoptic.com